Forming block



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FORMNG BLOCK.

Application filed April 25, 1922. Serial No. 556,477.

This invent-ion relates to drill sharpening machines, andv especially to the forming blocks used in conjunction therewith.

vOne of the principal fac-tors which the eiciency of a rock drilling plant depends is a correctly designed, properly made drill steel bit. No matter how efficient the compressing plant, the mining method, and the rock drills, or how careful the operator, if the bit is dull or of incorrect shape, the rock is not cut, expensive energy is wasted, and money and time are lost.

The many advantages of properly formed and sharpened drill bits are increased drilling speed, reduced drill and steel breakage, ease of operation, and lower sharpening costs, all resulting in the increased efficiency of rock drilling.

ln the design oit a good bit, the cutting and staying qualities should be considered as well as the ease and rapidity with which it can be formed and sharpened, rlhe most important of these, of course, is the rapid cutting quality because the object in view is to cut the maximum roclr in the minimum time.

The consensus of opinion is that under average conditions a goed bit for powerdrilling work should embody the following features: Y

lt must take full advantage of the chipping and fracturing of the rock. In a bore -hole'there is a certain depth to which rock will fracture when struclr by a sharp tool. If the tool is driven deeper than this'it will not fracture the rock; it will crush it. lf the cutting edge 0f the bit is blunt it will not get full advantage of the fracture, and considerable of the forcewill be expended in crushing orv pulverizing.

T he wings of the bit should be as thin as is consistent with standing-upv quality to allow for the ejection of the cuttings. lf the wings are left too heavy, there is not suflicient space for the escape ofthe cuttings,

and consequently they are'held in front of the bit and continually churned and ground; the bit does not easily reach solid roclr, and the blow loses a large proportion of its cutting power before it reaches the rock.

rlhe bit must be perfectlyfree in the hole at all times; because of the tendency of the rock to fracture, the drill hole will be a trifle larger than the cutting edge. lf the bit isy so designed that the cutting yedge has the same'diameter as the distance across the Vdi.arnetrically opposite corners and remains soV until dull, it will always remain free in the hole. l

The bit must allow equal wear on all corners. If the bit is not symmetrical, that is, if the ends of all cutting edges are not the same distance from the center of the bit, the longest end will cut a groove on the side of the bore hole and a rifled hole will result. Furthermore, the wear is unequal and the uneven or extra strains produced in the steel will oftenca-use breakage. rlhe rotation of the d 1ill is impeded and certain parts of the machine subjected to excessive wear.

.Allowable loss of gauge is also an important factor, for the greater the loss, the

larger must be the diameter of the starting steel to insure a certain diameter of hole at a fixed depth. This larger diameter means a loss ofpower. Operators who believe the gauge should beretained,r irrespective of the amount of power used,often Irun-the edges of the wings of the bit back about one inch in a line parallel to the axis, thus changing the bit to a reaming tool. lf this is done, and the cutting ledges wear a little, the shoulders begin to bind and lsticlr against the sides of the hole and it must be reamed out to a size which will allow the bit to move forward. "When such a bit is removed from the hole it will-show greater wear on the edges of the wings than on the cutting edges. As the bit is usually as hard one-half inch back as on the cutting edge, it is reasonable to suppose that there has been as much work done in wearing the steel of the wings as in wearing an equal amount of the cutting edge. ln other words as much, if not more, power is in this manner expended in reaming the hole than in cutting it. Furthermore the rock drill is designed to cut rock by means of a blow. It is not a reaming machine or tool, and therefore as soon as a bit is cutting or reaming the side of the hole it is retarding the action of the drill and putting overstrains on the rotating mechanism. Power expended in reaming is power lost. From this it is apparent that because of the rapid loss of power and the wear and tear on the rock drill, little of the eiiciency of the bit should be sacrificed to the reaming qualities.

From the foregoing it can readily be seen that the formation of the wings, the thicknessk thereof, the corners produced and the angle of the cutting edge, form an important factor. kThe object of the present invention is to insure such uniformity and thereby increase the general cutting efiiciency of the bit.

The invention furthermore embodies a special type of forming block whereby correct gauging is secured, uniform and proper thickness of the wings maintained, and properly reinforced corners and cutting angles at the face of the bit.

The invention also embodies a forming block whereby uniform and equal length of the cutting edges may be obtained so that succeeding steels will follow without binding, thus relieving the drilling machine of unnecessary torsional strains in rotating the drill steel.

Further objects will hereinafter appear.

The invention consists of the parts and the construction, combination and arrangement of parts as hereinafter more fully described a-nd claimed, having reference to the accompanying drawings, in which- Fig. 1 is a side elevation partially in section of a suitable form of drill sharpening machine.

Figs. 2 and 3 are side elevations of the respective forn'iing blocks employed.

Fig. 4 is a side elevation of the forming blocks showing them in closed position.

Fig. 5 is a plan view of the lower stationary forming block.

Fig. 6 is a side elevation of the forming blocks showing the gauging operation, to insure uniform diameter of the wings of the bit.

Fig. 7 is an end view of the forming blocks showing the gauging operation.

Fig. 8 is a detail view showing the form of steel employed from which the bits are formed.

Fig. 9 shows the end of the steel when upset and before it is placed between the forming blocks.

Fig. l() is a view of the bit end of the steel after it has been treated by the forming blocks. l

Fig. 1l is a view of the bit end of the steel and the die and showing the dolly cooperating therewith.

Fig. 12 is a view of the completed bit.

Referring to the drawings in detail, and particularly to Fig. l, A indicates in general the base of a suitable form of drill iiorming and sharpening machine. The particular machine illustrated in this instance is known in the trade as a Leyner drill Sharpener. lt is provided with a lower or stationary vise 2 and an upper or movable vise 3; the upper vise being carried by a cross head rod 4 and a differential piston 5, which is secured on the lower end of the cross hea-d rod by a lock-nut 6. The stationary and movable jaws carry the respective halves of the diesv and forming blocks employed. For instance the die with which the dolly cooperates is indicated at 7, the forming blocks at 8, a shearing knife 9, and other forms of dies and tools which may be used for various purposes.

The lower stationary portion of the machine consists of a main cylinder l0 and the base A.. The end of the piston 5 is movable in the cylinder l0, while the smaller end of the piston slides in an auxiliary cylinder ll carried by the case. Air under constant pressure, supplied to the base through the intake 12, acts upon the small diameter of the diierential piston and normally maintains the cross head and the movable jaw supported thereby in the raised position shown; the upper portion of the large diameter of the piston being open to the atmosphere for exhaust. By movement of the lever 14;, .a portion of a. revolution, valve 15 is raised. This causes the eX- haust and admits air from the base to the upper side of the large diameter of the differential piston. This forces the piston and cro-ss head down against the constant pressure actingon the small dia-meter of the piston. Atmosphericl air trapped beneath the large diameter of the piston is restricted in its escape by an ingenious arrangement of ports in the main cylinder and the throttle valve chest. This cushions the movement of the crosshead and the movable jaw at the end of the stroke just enough to prevent injury to the machine, but does not interfere with its clamping or forging action.

A brief description of the general construction and operation of the machine is thought Sufficient in this instance as the machine proper does not form any partv of the present invention. lt is for this reason briefiy disclosed to show the position of the forming blocks forming the subject matter of the present invention and the manner in which they are operated.

The forming blocks are secured in the stationary and movable jaws of the machine in any suitable manner and they are perhaps best illustrated in Figs. 2, 3, 4l and 5. The forming tool consists of an upper block, as indicated at 16, and a lower block, as shown at 17. These blocks are practically identical in construction and may be constructed of any suitable material as required. By referring to Figs. 3 and 5, it will be seen that the lower block is substantially rectangular in shape and that it is practically separated into two sections by a centrally positioned slot or groove 18, which extends from the front to the rear of the block. This groove is alsovformed in the upper block and the grooves are provided for the reception of the wings of the bit during the forming or sharpening thereof; this being best illustrated in Fig. 4, the wings under formation being indicated by dotted lines at 19 and 20. Formed at the front end of the slot 18, in the lower forming block, is a bearing lug 21 and journalled therein is a screw rod 22 on which is adjustably mounted a gauge member 23. The outer end of the rod is provided with a turning member 24, whereby the gauge member 23 may be retracted or extended, that is the gauge member 23 is threaded to receive the rod 22 and as the gauge member is secured against rotation by the sides of the slots 18, it functions as a nut and will have a forward or rearwardpsliding movement in said slot when rod 22 is turned. The upper end of the gauging member, indicated at 24, engages the center of the steel and thereby limits the inward movement of the same during the placing of thesteel and during the forming operation.

For the purpose of properly drawing out the wings to a point, and also for the purpose of forming a cutting edge on the wings, as indicated at 25, see Figs. t and 10, two pair of dogs are employed, one pair in each block; these dogs being indicated at 26 and 27. Each pair of dogs is pivotally supported in its respective block as indicated at 27, and it is normally held in a raised or projected position by means of spring actuated plungers 28. The forming blocks are also provided with wing gauges as shown at 29, the function of which will hereinafter be described, and they are furthermore provided Vwith. inclined faces, as at 30, which also serve an important function hereinafter to be more fully disclosed.

ln actual operation. we will suppose that an ordinary round steel bar, such as indicated at 31, see Fig. 8, is employed and that the end thereof is to be upset and formed to produce an efficient type of cutting bit. If this is the case the round steel 31 is first placed between the dies 7 and the jaws brought together. A. dolly, such as indicated at 32, in Fig. 11, is then forced inwardly against the steel in the die and the end of the steel will be upset and assume the form indicated at 33, see Fig. 9. The end of the steel when so upset and formed is neXt placed between the forming blocks 8. The steel is placed centrally of the respective forming bloclrs and shoved inwardly until engagement is made with the stop ofthe gauging member shown at 2li. The grooves or channels 18 form a guide for the steel when it is being placed and insures perfect centering of the saine. These groovesl furthermore receive the wings of the bit as they are formed.

With the upset steel, as shown in Fig. 9

.placed in proper position between the forming blocks, the jaw 3 of the machine is lowered and two wings will be properly formed. The jaws are then raised and the steel turned one-half a revolution to permit formation of the opposite wings. This operation is repeated again and again until the wings have been drawn out to the desired extent.

The pivotally supported dogs form an important function during ythe forming oper-- ation of the wings, as they first of all assist materially in drawing out the points of the wings, and secondly form substantially the cutting angle desired as indicated at 25. After the wings have been drawn out to the approximate diameter required, the bit is removed from between the forming blocks and they are next placed between the wing gauges indicated at 29, see Figs. 6 and 7. The adjacent faces of these gauges are inclined,l as at 36, and will for this reason force the points of the bit inwardly and shape them as shown at 37, in Fig. 11. The respective wings will in this manner acquire a uniform length and will squash the thin drawn out edges baclr into position where they may be properly acted upon by the dolly 32 when the bit is placed in the die shown at 7 in Fig. 11. l/'Vhen so'placed in the die, the dolly 32 is forced against the face of the bit and the final operation of forming or sharpening the bit will be completed; the completed bit being illustrated in Fig. 12.

By referring to Figs. 2, 3, L and 6, it will be seen that the face of the dies is slightly inclined as shown at 30. This is also of material importance as it decreases the thickness of' the wings of the bit as in.- dicated at 10. see Fig. 10. that is the maximum thickness of the wings is that illustrated at /1-1. The outer point is slightly reduced and angular faces are formed by the surfaces 30, and the final cutting edge being that indicated at 25. This cuttingedge is slight-ly rounded due to the corrugated rollino' surface l2 of the dogs` but the proper `b l n u formation 1s imparted to the cutting edges when the dolly is brought into engagement therewith asillustrated in Fig. l1. A swaging action takes place when the dolly is forced into position with relation to the die 7, and the rounded portion of the cutting edge, illustrated at 25, is thus flattened out to the proper angle. The inclined surfaces 4:0 are similarly partially straightened out and the normal or maximum thickness of Wing, such as shown at 4l, is substantially assumed. A perfect bit is in this manner obtained and the general efficiency of rock drilling should be materially increased, that is the Wing gauges 29 insure a uniform diameter; the forming blocks insure uniform thickness of the wings; the corrugated surfaces l2 of the dogs insure the vproper draiving out of the corners, and final correct formation and cutting angle is obtained by the dolly and the die.

lVhile certain features of the present invention are more or less specifically illustrated, l Wish it understood that various changes in form and proportion may be resorted to Within the scope of the appended claims, similarly that the materials and finish of the several parts employed may be such as the experience and judgment of the manufacturer may dictate or various uses may demand.

Having thus described my invention, vwhat l claim and desire to secure by Letters Patent is l. A forming tool of the character described comprising a pair of substantially rectangular shaped blocks, each of said blocks being provided With adjacent forming surfaces and said surfaces being channeled from end to end, and a pivotally mounted dog forming a continuation of each forming surface, the pivotal ends of the dogs being provided with gripping faces adapted to gradually grip and form cutting edges on the bit during movementof the dies towards each other.

2. A forming tool of the character de scribed comprising a pair of substantially rectangular' shaped blocks, each of said blocks being provided with adjacent fornr ing surfaces and said surfaces being' chan-i neled from end to end, a pivotally mounted deg forming a continuation of each forming surface, means for normally maintaining the dogs in a raised position, and a corrugated rolling and gripping surface formed on the pivotal end of each dog.

3. fr forming tool of the character described comprising a pair of substantially rectangular shaped blocks, each of said blocks being provided with adjacentforming surfaces and said surfaces being chan neled from' end to end, a pivotally mounted dog forming a continuation of each forming surface, means for normally maintain ing the dogs in a raised position, a corrugated rolling and gripping surface formed on the pivotal end of each dog, and a gauge member carried by one of the forming blocks.

4t. A forming tool of the character de scribed comprising a pair of substantially rectangular shaped blocks, each of said blocks being provided with adjacent forming surfaces and said surface-s being channeled from end to end, a pivotally mounted dog forming a continuation of each forming` surface, means for normally maintaining the dogs in a raised position, a corrugated rolling and gripping surface formed ou the pivotal end of each dog, and a longitudinally adjustable gauge member carried by one of the forming blocks.

5. A forming tool of the character described comprising a pair of substantially rectangular shaped blocks, each of said blocks being provided with adjacent forming surfaces and said surfaces being channeled from end to end, a pivotally mounted dog forming a continuation of each forming surface, means for normally maintaining the dogs in a raised position, a corrugated rolling and gripping surface formed on the pivotal end of each dog, and a Wing gauge formed on the end of each forming block.

G. A forming tool of the character described comprisingT a pair of substantially rectangular shaped blocks, each of said blocks being provided with adjacent forniing surfaces and said surfaces being channeled from end to end, a pivotally mounted dog forming a continuation of each forming surface, means for normally maintaining the dogs in a raised position, a corrugated rolling and grippingsurface formed on the pivotal end of cach dog, and a Wing gauge formed on the end of each forming block, said wing gauges having oppositely inclined forming and gauging surfaces.

t. ln a forming block of the character dcscribed, a substantially horizontal flat forming surface, a slightly angular forming surface forming a continuation thereof, and a combined rolling and gripping member forming a continuation of the inclined surface.

8. In a forming bloei; ofthe character described, a substantially horizontal flat forni ing surface, a slightly angular' forming surface forming a continuation thereof, a combined rolling and gripping member forming a continuation of the inclined surface, said member comprising a pivotally mounted dog, means for holding the dog in a raised position, and a corrugated gripping surface on the pivotal end of the dog.

9. ln a formino block of the character described pair of garated formingsurfaces, a rolling and gripping member forming a continuation of each surface, a channel lle formed in the bleek between said surfaces formed n the block between seid surfaces end Separating the same, and. e gauging and separating the same, e bearing lug at one member disposed in said channel. end of the channel, e screw red turnebly 10 10. In a 'forming block of the character mounted therein, and a gauging member 5 described e pair of separated formng sursldably mounted in the slot and yhaving a feces, a rolling and gripping member forrnthreaded engagement With the rod.

ing a continuation of each surface, a channel EDWARD R. HARTIN. 

